On the suitability of admixing sand to metallic iron for water treatment

This communication clarifies the relationships between sand addition and the sustainability of iron/water systems for environmental remediation. It is shown that any enhanced contaminant removal in an iron/sand/water relative to an iron/water system is related to the avoidance/delay of particle cementation by virtue of the inert nature of sand. The argument that sand dissolution produces protons (H+) to sustain iron corrosion is disproved by the very low dissolution kinetics solubility of SiO2-bearing minerals under environmental conditions. This demonstration corroborates the concept that aqueous contaminant removal in iron/water systems is not a process mediated by electrons from Fe0